Punch and die assembly



Nov. 7, 1944. 1.. v. WHISTLER ET AL PUNCH AND DIE ASSEMBLY Filed Dec. 15, 1943 g a a a g w z 26 a g m Z W my a a; E aw Patented Nov. 7, 1944 PUNCH AND DIE ASSEMBLY Lawrence V. Whistler and Sanford A; Whistler, Kenmore. N. Y.

Application Decemberlii, 1943, Serial No. 514,583 11 Claims. (Cl. 164-124) Our invention relates to a punch and die assembly and to the punches and dies used in the assembly.

Where heretofore sheet metal has been perforated with the perforations or punch holes closely spaced apart, it has been necessary to run the sheet metal or work-piece through the die-set or press a plurality of times, This necessitated the setting up of the punches and dies a second, third, or more times and the passing of the workpiece through the die-set or press a like number of times, depending on the closeness of the spacing of the punch holes in the work-piece.

Eilorts have heretofore been made to reduce the size of the punch and die-couples so that each occupies a comparatively small area and thus,

enable a close disposition of such couples or units, and while this has been accomplished to a certain extent, there still remains the need of running the work-piece through the die-set or press a plurality of times when the perforations or holes in the work-piece are closely spaced apart.

It is the primary object of our invention to provide punch and die-couples in a punch and die assembly which can be positioned within a dieset in closer relation, one to another, than has heretofore been possible.

It is also an object 01 our invention to provide a'punch and die-couple in which both the punch and die are formed of steel rod material and in employing in association therewith punch and die holder-plates having punch and die receivingopenings therein micrometrically conforming in diameter to the diameters of the punches and dies, the openings in the punch holder-plate and the die holder-plate being axially alined to assure axial and concentric relation between the punches and the dies entered in said openings.

Our invention also has for its. object to pro- .vide a punch and die-couple in which the bodies of th punch and die are ground concentric with the punch point of the punch and the punch ill).

hole opening of the die; the concentric grinding I of the bodies of the punch and die assuring a snug fit of both in their respective punch and die holding-plates.

Another object of our invention is to utilize mere insertion of said punches and dies in their respective holding-plates.

A still further object of our invention is to provide punches and dies of the type mentioned with means to prevent longitudinal sliding movement of the punches and dies in their respective receiving-openings; this being preferably accomplished by providing an exterior screw thread along the portion of the punches and dies which are entered in the holding-plates; the thread when used for such purposes fitting loosely and serving only as a means for holding the punches and dies against longitudinal movement in their respective holding-plates; the walls of the receivlug-openings in said plates and the inserted portions of the punches and dies ground concentric with respect to the punch point of the punch and the punch-hole in the die being the sole means of providing concentric relationship or axial alinement of the punches with respect to the dies.

It is a still further object of our invention to provide in a punch and die assembly, punches and dies capable of use in connection with strippingmechanism which may be either used in the form of an individual stripping-device associated with each punch or in the form of general stripping mechanism common to all punches and dies; both forms of mechanism enabling sheet metal or like material to be punched or perforated in much closer spaced relation than has heretofore been possible: and when using die-stripping mechanism common to all punches and dies in the assembly, enabling the sheet metal to be punched or perforated with the centers of the punch holes or perforations in the metal spaced only a small fraction of an inch farther apart than the diameter of the drilled or reamed openings in the punch and die holding-plates and the diameters of the bodies ofthe punches and dies.

With the above and other objects in view, our invention consists in forming the punches and dies of cylindrical steel rod material having the exterior surfaces, or at least the exterior surfaces of the attaching ends thereof, round and concentric with the punch points of the punches and the punch-holes of the dies and having their holding-plates drilled and reamed with openings or holes to receive the punches and dies and to conform micrometrically to the ground portions of the punches and dies so that contact between the ground surfaces of the latter and the walls of said holes or openings will assure axial alinemerit of each punch and die forming a die-couple.

It also consists in providing the entering or attaching portions of the punches and dies with retaining means, preferably in the form of screwthreads fitting corresponding screw-threads in the holding-plates; said co-acting screw threads preferably fitting loosely; said retaining means, in any form used, serving merely to prevent accidental longitudinal movement of said punches and dies; thus holding the punch end of each punch in properly spaced relation to its mating die.

The invention further consists in the novel features of contruction and in the arrangement andcombination of parts hereinafter described and more particularly pointed out in the subjoined claims.

In the drawing:

Fig. l is a front elevation of a die-set showing a plurality of punch and die-couples assembled therein, in association with stripping mechanism common to all punch and die-couples.

Fig. 2 is a sectional view through a portion of the ram and shoe of a die-set, the punch holdingplate, the die holding-plate, a punch and. diecouple, and an individual stripping-device applied to the punch of the die-couple, the punch and the inserted end of the die being shown in elevation.

Fig. 3 is a similar sectional elevation, showing the entering ends of the punch and die tapered.

Fig. 4 is a similar sectional elevation showing a modified form of die element.

Fig. 5 is an enlarged side elevation of the entering or securing end of a punch or a die illustrating in comparison with the'preceding figures the variation in the number of thread-convolutions which ma be employed.

Fig. 6 is a sectional elevation on a still further enlarged scale, showing the screw threads, when employed, of a punch or die loosely threaded into the receiving-opening formed in the punch holding-plate Or the die holding-plate, as the case may be.

Having reference to the drawing in detail, the numeral l designates a die-set, considered as a whole; it being of the conventional type usually employed in connection with perforating or stamping presses. This die-set has the usual shoe or bed-member 8 provided with guide-rods 9 which extend upwardly therefrom and which fit into guide-holes usually provided in the rammember ID of the die-set. The ram-member has a shank i i for fastening said member to the ram or other movable part of a press. The shoe is usually fastened to the bed or bolster of the press and in this particular punch and die assembly, the

- punch holding-plate i2, sometimes referred to as a mounting-plate, is comparatively thick and it is secured to the underside of the ram ill in any approved manner. A die-holding plate i3 is secured to the upper surface of the bed or shoe of the die-set and likethe punch holding-plate. is also comparatively thick, as clearly shown in Fig. 2. The punch holding-plate and the die holdingplate are drilled and reamed to provide openings i4, i5, respectively. These openings are formed in the respective holding-plates in accordance with a template, or under punch-point measurement, to conform to the spacing of the perforations or holes which are to be punched in a workpiece, and they are used in couples; the opening or each opening in the punch holding-plate l2 being in perfect axial or concentric alinement with an opening IS in the die holding-plate and to accomplish this, the two plates are drilled and reamed simultaneously so that no variation in aeeaose the openings axially. or concentrically considered, can occur. This is now common practice for assuring axial alinement of a punch with respect to its mating die, although as such punches and dies have beenpreviously used, they differ widely from the means for securing the punches and dies forming part of this invention. The openings M and E5 in the holding or mounting-plates are drilled and reamed micrometrically to a definite. size for a purpose to presently appear hereinafter.

The punch or punches of this invention, designated by the numeral it, are constructed of cylindrical steel rod material but may, if desired, be machined to cylindrical form and they are in most instances provided with reduced operating or punching ends, whichmay be referred to as punch points il. It is, of course, to be understood that where the hole in the work-piece, designated by the numeral i8, is of a diameter conforming to that of the body portion W of the punch, no reduction in diameter will be required at the operating end of the punch. Whether formed of cylindrical steel rod material or machined to cylindrical form, the exterior surface of the body portion, or at least that of the inner or securing end of the punch, is ground concentric to the axes thereof and to conform to its receiving-opening if! in the punch holding or mounting-plate i2 so that the exterior surface of the body portion, and especially the securing end thereof, will have the same micrometric reading as the diameter of the opening it receiving it; thus assuring a perfect and snug fit of the cylindrical entered portion of the punch with the wall of the opening receiving it. This, therefore, pre= vents the minutest lateral or swaying movement of the operating end of the punch, particularly so because of the increased thickness of the punch holding-plate over holding-plates now commonly used. By increasing the thickness of the holdingplate over that commonly employed, a receivingopening of considerable length is provided in the plate. The contacting surfaces of the punches are consequently of considerable length which, in addition to the snug fit of the punch in its receiv= ing opening, assures maintenance of the punch in true vertical position at all times and under all conditions.

The dies, designated by the numeral 20, are preferably also formed of cylindrical steel rod material, but may also be machined to cylindrical form if desired. Like the punch, its exterior surface, or at least the exterior surface at the inner end thereof, is micrometrically sized to the opening i5 in the die holding-plate i3 so that it also has a snug fit in said opening and by reason of the holding-plate i3 being comparatively thick, the entered region of the die is of considerable length, thus also assuring maintenance of the die in perfectly vertical position. Each die has a punch hole 2! formed therein, the size of which conforms to the operating end or punch point of its mating punch and it is provided laterally with a slug opening or passage 22 with which the die opening 2| is in communication.

Since the receiving openings i4 and ill in the holding-plates i2 and i3 have been drilled or reamed in perfect axial alinement, the mating punches and dies are, of course, assured axial alinement when secured to their respective plates or mountings, and it is especially to be noted that the exterior surface of the punches and dies, and particularly the exterior surfaces of the entered portions thereof, are concentric with the punch holes 2| in the dies and the punch points ll of the punches.

When used asthus far described, it will be apparent that perforations .or holes will be punched in a work-piece with their centers spaced apart much closer than would otherwise be possible, and this is particularly true when providing the punch mounting or plate I2 with stripping mechanism of the type shown in Fig. .1, wherein there are stripping devices 23 spaced apart and located in areas not occupied by the punches or dies. These are so arranged that they exert pressure against the work-piece l3 downwardly and retain the work-piece against the upper ends of the dies when withdrawing the punches from the openings punched in the work-piece, and as shown in Fig. 1. these stripping devices are'distributed so as to avoid bending. or buckling of the work-piece. When using stripping devices common to all punches and dies, the punches and dies. if used as thus far described, could be arranged in such close'relation to each other that the body portions of adjacent punches and dies would lie in contact with each other, but preferably for all practical purposes they are slightly spaced apart and the spacing between punch and die-couples may vary, as shown in Fig. 1,'dependin-g on the locations which the perforations or holes are to have in the work-piece.

In Fig. 2 we have shown a stripping-device 23 applied directly to a punch. This stripping-device is of a construction'now in use and needs only slight detailed. description. It comprises a header 24 secured to the punch l6 by means of a set screw 25. A shoe 26 adapted to bear against the upper surface of the work-piece, and slide rods 21 secured at their lower ends to the shoe 26 and slidable in the header 24, means being provided within the latter to limit the downward movement of these slide rods. Surrounding the slide rods are springs. 23 which force the shoe 26 against the work-piece and which yield to upward pressure.

It will be clear from the brief description of the stripping-device shown in Fig, 2 that simi lar stripping-devices may be used in the manner shown in Fig. 1, also that instead of these stripping-devices being used in areas not occupied by punches, they may be used in direct association with punches which are sufllciently spaced apart in the punch and die assembly that they will not interfere with adjacent punches.

While the punches and dies may be used as thus far described, we prefer to employ screw threads 29 at the entered portions of the punches and dies, the convolutions of which are widely spaced'apart so that in the valleys or regions 30 between their adjacent circumferential portions, the truly ground cylindrical portions of the punches or dies are maintained and relied upon to assure axial and concentric alinement of the mating punches and dies. The convolutions of the screw threads on each punch and die conforms to an internal screw thread 3| in the receiving-opening H or l of the holding or mounting-plates, as the case may be, but no portion of this screw thread i relied upon to maintain axial alinement of the parts of a punch and die-couple. The screw threads of the punches or dies loosely fit the screw threads 3| formed in the mounting-plates and the co-operating threaded portions of both the punches and dies and their holding or mounting-plates are employed solely as a means for holding the punches or dies in ltheir relatively spaced-apart positions and in no manner determine the axial or concentric relation between the punch and die members of a die-couple.

In. the modification shown in Fig. 3, the entered ends of the punches and dies are tapered, as shown at 32 and 33, and the openings in the mounting-plates are in that case designated by the reference characters I4 and I5, respectively. The openings are therefore tapered from the innor surfaces of the mounting-plates outwardly; that is to say, upwardly from the under surface of the punch mounting-plate l2 and downwardly from the upper surface of the die mounting-plate l3. These openings are reamed or otherwise machined microme rically true and the tapered ends 32 and 33 of the punches and dies are ground to have the same micrometric reading at corresponding points in their lengths as the openings in the mounting-plates so that a true axial and concentric alinement of the punch and die elements is assured.

It may here be stated that in the preferred construction of our punches and dies, shown for example in Fig. 2, both the punch and the die are inserted into their respective mountings to occupy the entire length of the receiving-openings formed in said mountings so that the ends of the punches bear against the underside of the ram ID of the die-set and the ends of the dies bear against the upperside of the shoe of the die-set. In the modification shown in Fig. 3 in which the entering ends of the punches and dies are tapered and the openings in the mounting-plates are correspondingly formed, the tendency of the punches and die during operation is to effect a tightening of both, since there is a constant hammering action taking place under operation of thedie-set. However, we prefer to employ screw threads 29 on the punches and dies so formed, which serve the same purpose as thoseapplied to the true cylindrical form of punch and die shown in Fig. 2.

In the modification shown in Fig. 4 we have shown a punch corresponding to the punch l6 illustrated in Fig. 2 and. therefore, have designated it by a similar reference numeral; the

die, however, is of a type in which a die-block 34 is removably entered in a, die-holder 35; this holder having a die-receiving opening 36 in communication with a slug opening or passage 31. pending shank 38 and it has the die-opening 36 axially alined therewith; the shank being constructed to micrometrically fit the opening ii in the die'mounting-plate and it is, of course, understood that the punch associated therewith. being similar to the punch l6 shown in Fig. 2, has its entering end like the entering end described for the punch shown in said Fig. 2. In this modification the die 34 can be easily removed from the die-holder and replaced with a die having a larger or smaller punch point openings, as may be required. This depends. of course, on the predesigned template or other layout for the work-piece, and necessarily a punch conforming in size to the punch point opening inv the die will then be substituted for thepunch used. In this case the shank 33 of the die-holder is also axially alined with the punch l6, regardless of the diameter of the This die-holder is provided with a de-.

opening it in the punch-mounting. In all instances the punch point hole in the die is in axial alinement with both the axes of the punch and the shank 38. The body portion of the punch i concentric with said shank and also with the punch point opening in said die. Therefore, while adapting our device so that dies of different sizes may be used in a single die holder in association with correspondingly ,sized punches, regardless of interchanges made, a positive axial alinement and concentric relationship between mating punches and dies is assured.

This invention does in no manner approach in similarity a screw or screw device used as a fastening means, because the screw convolutions in our invention is not prerequisite to the successful use of the punches and dies, but is solely employed to guard against longitudinal slipping movement of the punches and dies, particularly when worn through long and constant use. Since the mounting-plates are preferably hardened and the ground exterior surface of the punches and dies are solely depended upon in connection with the corresponding micrometric sizing of their receiving holes, the convolutions of the screws being somewhat loosely fitted in no manner affect the axial and concentric relationship of their punches with their mating" dies.

In ordinary screw fastenings, variations from a perfect cylindrical form for the body always occur and the spiral valleys betweenthe helixes of the screw thread are never employed true to the axes of the screw. In such cases, the thread of the fastening device is the means depended upon to enter thescrew device in an object, or in objects to be connected together. This is the exact opposite of our invention, wherein the body portion of the punch and die is the determining factor in so far as axially and concentrically alining it with respect to a, mating element. The screw portion of the device, when its use is resorted in our invention merely serves to retain the punch and die in their respective mountings, and has absolutely no effect on the alining of the punch with its mating die.

It will be apparent from the foregoing that our invention contemplates the forming of an opening in a support, housing, or mounting which is of a micrometically determined diameter, and an operating element adapted to be entered in said opening and conformable micrometrically to the diameter of said opening,

iii?

the peripheral surface of said element having its In its more specific or ment in one direction and to move the latter out of the opening when rotating the same in an opposite direction.

We, of course, stress the fact that the spiral projection on the body portion of the element to be fastened in place and the convolutions of the corresponding spiral screw-groove in the opening are widely spaced apart so that reliance is solely placed on the surface of the element between said projections to axially position and screw the element in place. Therefore, it is to be understood that the co-acting screw-threads, male andfemale, are not essentially employed for fastening the operating elements in place, but more particularly to facilitate the insertion of said elements in their respective receiving openings and their removal from said openings. The screw-threads, of course, prevent accidental displacement of said operating element, when in their openings, under a straight-line movement and may, therefore, be considered as incidentally aiding in holding the elements in their respective openings under certain operating conditions.

In referring to a comparatively thick mounting in the following claims, we mean a mounting which in thickness has a greater measurement than the diameter of the element of the punch device to be fastened therein, so that a comparatively long bearing surface is provided. for the element within the mounting.

Having thus described our invention what we claim is:

I. In combination, a comparatively thick mounting having a cylindrical opening of micrometrically determined diameter therein, and an element 01 a punch device having a cylindrical securing portion exteriorly concentrically true to its axis and adapted to tightly but removably fit said opening with close contact at all points of its entering region, said opening being provided with an internal screw thread having its convolutions spaced apart to provide'cylindrical contact regions therebetween and said entering region being provided with an exterior screw thread and having spaced-apart'contact regions providing cylindrical portions corresponding to the spaced-apart regions of said first-mentioned convolutions, the screw threads of said entering region fitting the screw threads of said opening in a comparatively loose manner and serving only to retain said element in said opening without disturbing the axial and concentric relationship between said entering region and the wall of said opening.

2. In combination, a comparatively thick mounting having a tapered opening of micrometrically determined progressive diameters and taper, and an element forming part of a diecouple having a tapered entering portion ground said screw-thread being threaded into an internal screw-thread which, in that case, the opening in the support, housing, or mounting is provided with; the outside diameter or top of the screw-thread on said root surface being smaller than the root diameter or bottom of said internal thread, so that at no time is the spiral projection or the convolutions of the element threads in contact with the root or inner portions of the opening threads. The element or male threads are therefore loosely fitted in the opening or female threads and are rotatably movable with the element, thus serving to enter the element in the opening by rotating said elealong its exterior to conform concentrically with the progressively changing diameters of said opening and to be thrust thereinto with its operating end projecting therefrom, said entering portion being of suflicient length and lying in firm contact with the tapered wall of said opening at all points in its circumference and effective length to prevent movement of the axis of said projecting operating end away from the extended axis of said opening, said opening having screw threads with its convolutions widely spaced apart and said element having mating screw threads loosely entering the convolutions of the screw thread in said opening to prevent sliding longitudinal movement of said element from said ope ins.

3. In a punch and die assembly, a pair of comparatively thick mountings having a plurality of pairs of openings formed therein, the openings of each pair being in axial alinement, a similar number of pairs of die-couple members formed of slender stock having entering portions conforming in cross section to the contour of said openings, said entering portions being micrometrically dimensioned to conform to said openings and being thrust into the latter to assure axial alinement of the members of each die-couple.

4. In a punch and die assembly, a pair of comparatively thick mountings having a plurality of pairs of round openings formed therein, the openings of each pair being in axial alinement, a similar number of die-couple members formed of steel rod material having cylindrical entering por tions ground along their exterior to micrometrically fit said round openings, said entering por tions being thrust into said openings to assure axial alinement of the members of each diecouple.

5. In a punch and die assembly, a pair of comparatively thick mountings having a plurality of pairs of round openingsformed therein, the openings of each pair being in axial alinement, a similar number of die-couple members formed of cylindrical steel rod material of a size to micrometrically fit into said openings, one member of each die-couple serving as a punch and other as a die and the latter having a punch receiving hole extending downwardly from its upper end and a slug passage formed in the side thereof in communication with said punch receiving hole, said punch and die member being axially alined by the mere insertion thereof into paired openings of said mountings.

6. In a punch and die assembly, a pair of comparatively thick mountings having a. plurality of pairs of round openings formed therein and provided with screw threads, the openings of each pair being in axial alinement, a similar number of die-couple members formed of cylindrical steel rod material entered in said openings, the ends.

of said die-couple members entered lnsaid openings being provided with screw threads to enter the screw threads of said openings and the portions of said entered ends between the convolutions of their screw threads being ground to micrometrically fit the walls of said openings, the insertion of said die-couple members into their openings assuring axial alinement of the members of each die-couple.

'7. In a punch and die assembly. a pair of comparatively thick mountings having a pair of round openings formed therein, the openings in said mountings being in axial alinement and by reason of the thickness of said mountings providing extended contact surfaces, a pair of members forming a die-couple, each member'being constructed of steel rod material and having at least a cylindrical entering portion adapted to be inserted into the axially-alined openings in said mountings, the entered portions of said members being ground to micrometrically fit said openings and thereby assure axial alinement of said members.

8. In combination, a support having a comparatively deep opening of micrometrically determined diameter, the wall of said opening having an internal screw-thread, the smallest diameter 'of its spiral groove or convolutions conforming to the micrometrically determined diameter of said opening, and an element entered in said opening whose peripheral surface micrometrically conforms in diameter, at least along its entered portion, to that of the micrometrically determined diameter of said opening, said'entered portion having an external screw-thread, the smallest diameter or root of which is at the periphery of said element.

9. In combination, a support having a comparatively deep opening of micrometrically determined diameter, the wall of said opening serving as a comparatively long contact surface and having an internal screw-thread whose convolutions are spaced apart to provide longitudinallyseparated contact regions for said contact surface, and an element of choice entered in said opening whose peripheral surface micrometrically conforms in diameter, at least along its entered portion, to that of the micrometrically de termined diameter of said opening, said entered portion having an external screw-thread conforming to said internal screw-thread to provide longitudinally-separated contact regions between its screw-thread convolutions for firm contact with the longitudinally separated contact regions of said opening.

10. In combination, a support having a comparatively deep opening of micrometrically determined diameter, the wall of said opening serving as a comparatively long contact surface and having an internal screw-thread whose convolutions are spaced apart to provide longitudinally-separated contact regions for said contact surface, and an element of choice entered in said opening whose peripheral surface micrometrically confonnsin diameter, at least along its entered portion, to that of the micrometrically determined diameter of said opening, said entered portion having an external screw-thread conforming to said internal screw-thread to provide longitudipally-separated contact regions between its screw-thread convolutions for firm contact with the longitudinally-separated contact regions of said opening, the screw-threads of said element fitting loosely, at least radially, those of the screw-threads of said opening and serving as a means to move said element in or out of said opening when rotated.

11. In combination, a support having a comparatively deep opening of micrometrically determined diameter, the wall of said opening serving as a comparatively long contact surface and having an internal screw-thread whose convolutions are spaced apart to provide longitudinallysepara'ted contact regions for said contact surface, and an element of choice entered in said opening whose peripheral surface micrometrically conforms in diameter, at least along its entered portion, to, that of the micrometrically determined diameter of said opening, said entered portion having an external screw-thread conforming to said internal screw-thread to provide longitudinally-separated contact regions between its screw-thread convolutions for firm contact with the longitudinally separated contact regions of said opening, the outside or top diameter of the screw-threads on said element being less than the root or bottom diameter of the screwthreads in said opening so that the outer regions oi the spiral projection or convolutions of the threads on said element do not contact the root or inner regions of the screw thread in said opening. i

LAWRENCE V. WHISTLER. SANFORD A. WHISTLER. 

